1. Field of the Invention
This invention relates to a method and apparatus for determining the head movement of a user of the device while the user performs certain specified physical tasks such as striking a golf ball or other sports and non-sports activities.
2. Description of the Prior Art
Many types of devices have been suggested for assisting a golfer in attempting to keep his or her head still while striking a golf ball. U.S. Pat. No. 1,637,406, U.S. Pat. 3,871,104 and U.S. Pat. 4,168,111 all disclose glasses that have been occluded to provide restricted vision for golf practice with the objective of assisting the golfer to keep his or her head still. U.S. Pat. No. 4,022,475 discloses a device which is attached directly to the lens of a pair of spectacles to assist in training a golfer to keep his or her head still. Similarly, U.S Pat. No. 3,228,696 and U.S. Pat. No. 3,487,549 show sighting devices directly associated with the lenses of spectacles for assisting a golfer in training.
All of the foregoing devices have shortcomings in that they require permanent modification of the golfer's spectacles to accomplish their purpose. Further, some of the devices add weight to the spectacles which make them impractical.
I have found that utilization of flexible optic altering membranes such as disclosed in U.S. Pat. No. 3,628,854 and U.S. Pat. No. 3,904,281 can produce a device which will not only assist a golfer in keeping his or her head still while striking the golf ball, but can also be useful in other sport activities such as croquet, billiards, T-ball, and shooting, as well as military uses where it is essential for those performing certain tasks to keep their heads still while performing the physical tasks.